Short version, add this to your Quadlet file (with whatever your service your gluetun Quadlet starts):
[Unit]
Requires=gluetun.service
After=gluetun.service
An article I found helpful when starting with Quadlets, which can even replace Docker compose. https://mo8it.com/blog/quadlet/


Sucks because I was strongly considering Framework for my next laptop. That said, it sounds like they may rethink their sponsorship approach with that bit at the end - they acknowledged the past issues with the Hyprland community but did due diligence, and they plan to involve the community more going forward.
May be empty promises but time will tell.